@weatherwest@mastodon.social

Daniel Swain @weatherwest@mastodon.social

· 15h ago

Update: Now Post-Tropical Storm Rachel has made landfall along northern Baja CA north of Ensenada. San Diego is thus spared brunt, but bands of torrential rainfall & severe thunderstorms are occurring from CA's Imperial Valley eastward into AZ, w/serious flash flood threat. #CAwx

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Daniel Swain @weatherwest@mastodon.social

· 5d ago

Boosted by @Dragofix@veganism.social

Just did some number crunching using latest (Oct 1) ECMWF seasonal data, and I must say that I've never seen such high predictive confidence in a very wet California winter. This is a truly extraordinary forecast amid a record-strength El Niño event. [Thread: please read to end.]

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Daniel Swain @weatherwest@mastodon.social

· 1w ago

Boosted by @trending@homestead.social

Global model ensembles are in strong agreement that a prolonged &anomalous nearly West-wide autumn heatwave will develop this week & persist for 10+ days. While some daytime records may be set, this event will be more notable for its persistence & breadth. [Thread]

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Daniel Swain @weatherwest@mastodon.social

· 4w ago

Boosted by @trending@homestead.social

Fielding questions re: this article w/bizarre factual errors. First, there's no "Montecito County" in CA. Second, 2 fires are actually in *Monterey,* & 3rd in *Mendocino*. Third, 60k ac have *not* burned in either fictional Montecito nor real Mendocino.🤨 https://www.latimes.com/california/story/2026-09-12/three-montecito-county-fires-burn-60-000-acres

Three Montecito County fires near Big Sur have burned nearly 60,000 acres

Los Angeles Times

Three Montecito County fires near Big Sur have burned nearly 60,000 acres

In Mendocino County, the total area burned by three fires grew to nearly 60,000 acres on Saturday.

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Daniel Swain @weatherwest@mastodon.social

· 2w ago

Boosted by @trending@homestead.social

In case you missed it live, this session was recorded and is now available! Remarkably, it now appears that Hurricane Polo has likely become the fastest-strengthening East Pacific hurricane on record (from tropical storm to category 5 strength in ~30 hrs)! https://www.youtube.com/watch?v=9uYYzUFoan4

A Category 5 hurricane west of Mexico? Plus: Thoughts on CA's El Niño-related emergency declaration

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

The conspicuous overlap between record-breaking warmth, dryness, and/or low snowpack and these fires is simply not a coincidence. The scientific evidence linking increasingly extreme fire weather, as well as increasingly extreme wildfires themselves, to climate warming is clear.

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Daniel Swain @weatherwest@mastodon.social

· 1mo ago

Boosted by @Dragofix@veganism.social

At last, a clearer forecast re: California and Marie! Marie is now weakening and will stay well offshore. However, confidence has increased that Marie's remnants will actually have a substantial influence on CA weather for the next 5-6 days! [Thread] #CAwx

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

Wildfire dynamics vary considerably across ecosystems, and that does argue for caution when making broad claims. But that's also precisely why it's so remarkable that there has been such severe fire activity across so many very different regions, and ecosystems, simultaneously.

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

From the boreal forests of Ontario to the moors of the Scottish Highlands to the grasslands & forests of Columbia River Plateau in NW U.S. to the maritime pine forests in France, these exceptional fires have been preceded, over weeks to months, by exceptional warmth and dryness.

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

The extraordinary wildfire outbreak across Oregon, eastern Washington, and southern British Columbia has become even more alarming amid critical fire weather conditions. Over 500,000 acres have already burned in OR & WA alone, and that number could be >1 million acres by Mon.

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

In France & Spain, the current wildfire outbreak has already necessitated the largest evacuation since WWII (since Dunkirk)--& largest ever in peacetime--of over 300,000 people. Widespread, though yet untold, structure loss appears to have occurred (including in suburban areas).

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

A major new wildfire outbreak is now underway across interior Pacific Northwest, with dozens (or more) new wildfires already popping up in eastern Oregon & Washington following tens of thousands of lightning strikes in region experiencing moderate to extreme drought. #ORwx #WAwx

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

Many of these fires, from British Columbia to the South of France, have exhibited extreme behavior even when ambient winds have been modest. This has largely been due to deep pyroconvective development, including full-fledged fire-generated thunderstorms.

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

Also striking is that the current extreme wildfire episodes are not only occurring in regions highly accustomed to them (like the Western U.S. and southern Europe), but also places with much less familiarity (like western Europe, and severe smoke impacts in the eastern U.S.).

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Replying to

In the United Kingdom, local firefighting agencies have been overwhelmed by vegetation fires during repeated heatwaves. Numerous forest and moorland fires, including some in the infamously damp Scottish Highlands, continue to burn.

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Daniel Swain @weatherwest@mastodon.social

· 1mo ago

Boosted by @trending@homestead.social

On Thu, Sep 10, at 10am PT I'll offer another major update regarding El Niño 2026, which is still expected to become strongest on record, summarizing latest observations and forecast updates. I'll also revisit potential California-to-global scale impacts. https://youtube.com/live/2v4k0nbUU1s?feature=share

September 2026 update: Extremely strong El Niño event remains on track for autumn-winter

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Daniel Swain @weatherwest@mastodon.social

· 1mo ago

Boosted by @Dragofix@veganism.social

On Friday, 9/4 at 10am PT, I'll have a another live Hurricane Maria-focused update on YouTube. I'll share the latest on the forecast evolution, answer your questions re: tropical storms/hurricanes and California weather, and try to dispel some myths. https://youtube.com/live/bbBUWnlPxMk?feature=share

Live update on Hurricane Marie and its potential to affect California weather over Labor Day weekend

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Daniel Swain @weatherwest@mastodon.social

· 1mo ago

Boosted by @Dragofix@veganism.social

The ECMWF seasonal ensemble has just updated for September, and it continues to suggest that a soon record-strength El Niño will exert a very strong tilt in the odds toward wet conditions across the U.S. southern tier, including all of California, the Lower Colorado, and SE U.S.

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Replying to

You, too, can submit a comment in 6 days that remain before the July 13 deadline. You certainly don't need to be a scientist, or work at a university, or for the federal government--all American taxpayers will be affected if this proposal is finalized. Some resources are below:

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

On Thu, Jul 9 at 11am PT, I'll have a livestream to discuss building "heat dome" that will eventually expand to encompass most of western & central US by mid Jul. I'll discuss impacts, including record heat, wildfire risk, & monsoon moisture/thunderstorms. https://youtube.com/live/Uys8re8I0BI?feature=share

Big "heat dome" to expand across West and Central U.S: Impacts on SW monsoon, wildfire, & more

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Growing signs of prolonged & potentially intense heatwave across SW by early Aug. A broad Four Corners ridge will strengthen far beyond usual levels on its western flank, possibly due in part to indirect effects from a yet-to-develop East Pacific hurricane. Details TBD. #CAwx

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

A major thunderstorm outbreak is unfolding across the interior Pacific NW. While not "dry thunderstorms" (w/briefly heavy showers), numerous wildfire ignitions are still likely due to strikes outside of rain cores, severe pre-existing drought, & heatwave to follow. #ORwx #WAwx

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

In case you missed it live, Tuesday's #ElNiño-focused virtual town hall event hosted by CA Sen Mike McGuire was recorded and is now available. This was a really constructive and worthwhile event; I'd strongly encourage folks to check it out! #CAwx https://www.youtube.com/watch?v=mmmXUkRp6-g

Super El Nino Town Hall

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Yesterday's "lightning bust" in eastern Oregon & Washington has already resulted in >100,000 acres burned & dozens of new wildfire ignitions. Many are in grass & brush and may be managed soon, but at least 10 are in heavier (forest) fuels and are taking off this PM. #ORwx #WAwx

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Replying to

The #GoldMountainFire near Ouray, CO (ignited yesterday) and the hours-old #WillowFire near Leadville, CO are both spreading rapidly and exhibiting extreme fire behavior and are burning mainly in high-elevation timber, with expanding evacuations in these areas. #COwx

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

NOAA SPC has once again upgraded today's fire weather risk in western Colorado & Four Corners region to "extremely critical"--marking rare third consecutive day. Multiple existing fires will likely make further large runs today, & new ignitions willl take off quickly. #COwx #AZwx

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Well, the extreme heatwave across the Northern Rockies/Northern Plains/Upper Midwest is living up to expectations with some locations (as of only 2pm local time) reaching or breaking all-time (any month) temperature records today in Wyoming and eastern Montana. #MTwx #WYwx

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

It's an honor to be receiving this year's California River Award from Friends of the River! I've taken a moment to reflect on the notion of rivers as "integrators of change"--from hydrological and human perspectives--during a period of rapid global change. youtube.com/watch?v=CFm0hyX8BJE&feature=youtu.be

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Replying to

Many professional and legal societies, as well as gov/constitutional scholars, have already opined--and there is almost universal alarm. For instance, statements from: American Physical Society: https://www.aps.org/initiatives/advocate-amplify/policy/federal-grants-rule-change American Meteorological Society: https://www.ametsoc.org/ams/about-ams/ams-statements/statements-of-the-ams-in-force/ams-summary-comments-on-the-office-of-management-and-budget-proposed-rule-on-regulation-for-federal-financial-assistance/

aps.org

OMB proposed rule for federal financial assistance

Find out more about the Office of Management and Budget's proposed federal grant funding changes and how APS is responding to this existential threat to the scientific community.

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

New Weather West post out this evening: "Unusually active April weather pattern to continue this week, and possibly beyond, as subtropical northeastern Pacific waters reach record warmth." https://weatherwest.com/archives/43838

Unusually active April weather pattern to continue this week, and possibly beyond, as subtropical northeastern Pacific waters reach record warmth - Weather West

Weather West - California weather and climate perspectives

Unusually active April weather pattern to continue this week, and possibly beyond, as subtropical northeastern Pacific waters reach record warmth - Weather West

April 19, 2026 - Daniel Swain - Milder temperatures in April than March, with much more precipitation; snowpack, however, remains extremely low What a strange Water Year it has been in 2025-2026! We started the WY with record rainfall during Oct-Dec across much of the central and south coast, including the wettest Oct-Dec period ever observed in Santa Barbara, Ventura, Kern, and #

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

I've got 3 live virtual public events on YouTube scheduled over next 8 days (see recent posts for links): 1) Aug 3, 1p PT: WA wildfire disaster & bigger picture 2) Aug 4, 6p: "Super El Niño Town Hall" (CA Sen. Mike McGuire) 3) Aug 10, 1p: El Niño update: The latest forecast

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

NOAA once again highlighting a rare, highest-end "extremely critical risk" region today around Four Corners/CO Western Slope for exceptionally adverse fire weather conditions amid severe drought. Numerous lightning holdovers are popping up during unusual summer wind event.

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Another month & another upward shift in predicted #ElNiño peak intensity (between Oct & Dec) in the multi-model ensemble median. The single most likely outcome is now a very strong ("Super") El Niño event; a record-breaking event is possible, but not guaranteed. Full steam ahead.

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Federal agencies are rapidly moving to curtail the ability of American scientists to collaborate internationally, and this is latest of several dramatic recent developments: "NSF policy set to ban almost all collaborations with Chinese scientists." https://www.science.org/content/article/new-nsf-policy-would-ban-almost-all-collaborations-chinese-scientists

New NSF policy would ban many collaborations with Chinese scientists

science.org

New NSF policy would ban many collaborations with Chinese scientists

Agency drops attempt to mitigate risk in favor of outright prohibition on working with a long list of Chinese research institutions

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

Replying to

In early May, a "Rex blocking" configuration will develop, allowing the PacNW to warm to well above average levels and California to cool back toward (but not below) seasonal averages. Additional mainly mountain showers are possible during this period. #CAwx

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

Replying to

Looking farther out into May, it does appear that a quieter, drier, and warmer pattern may be on the way for CA as modest ridging replaces persistent troughing. Additionally, the extreme marine heatwave persists in Pacific, which will boost coastal temps further.

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

Replying to

Total precipitation will be mostly light at lower elevations, with another modest soaking possible in some NorCal mountain regions. A few showers are also possible in SoCal. Notably, the PacNW will remain almost completely dry.

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

There are growing indications that large, intense, & perhaps record-breaking mid-atmospheric high pressure system (aka a "heat dome") will develop somewhere between Rockies & Central Plains by mid-Jul. This could bring a widespread & severe heatwave across much of the U.S.

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

Replying to

Looking ahead to mid-May, there is now pretty strong inter-ensemble agreement regarding the development of a much more pronounced Western ridge once again, with the potential for a significant heatwave at that time. This would mark a major pattern shift, so stay tuned!

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Daniel Swain @weatherwest@mastodon.social

· 2mo ago

Zooming in on Oregon, the enormous scope of ongoing wildfire outbreak is clear. Numerous large smoke plumes from dozens of active fires--which have now burned over 1 million acres in Oregon alone--are casting a broadening pall across the interior Northwest & N. Rockies. #ORwx

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

On Monday at 2pm PT, I'll discuss whether this weekend's showers might be the last of the season, where we currently stand water & snow-wise, and also the potential for a significant mid-May heatwave in California and across the broader West. https://www.youtube.com/live/Og4MUXnTQH0

One more round of spring showers for California before potentially significant mid-May heatwave

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Daniel Swain @weatherwest@mastodon.social

· 5mo ago

Talking weather and climate with with Daniel Swain, UC ANR climate scientist: Conversation re: record-smashing warm month of March for the western U.S. and what it means for the region going forward. https://open.spotify.com/episode/5Xj3yof5cxGHrSINFbVv7f?si=cQ-GPzJ4R7CEy2ANq3LYaQ&nd=1&dlsi=9c5da067ff5b4cac

Spotify

Daniel Swain Climate Scientist

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Replying to

The American Physical Society has offered a nice overview of the most science-relevant implications of these new proposed rules, as well as a tool to help craft your response: https://www.aps.org/initiatives/advocate-amplify/policy/federal-grants-rule-change

aps.org

OMB proposed rule for federal financial assistance

Find out more about the Office of Management and Budget's proposed federal grant funding changes and how APS is responding to this existential threat to the scientific community.

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Daniel Swain @weatherwest@mastodon.social

· 3mo ago

Replying to

Countless scientific and professional societies in the United States have already issued public statements of alarm, and many have submitted formal public comment to the federal government--as have thousands of individuals. You can, too, directly via: https://www.regulations.gov/commenton/OMB-2026-0034-0001

regulations.gov

Regulations.gov

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